Option to have Realm app users in an Atlas collection
It would make a lot of sense to me if one could configure a Realm app to use a collection in the Atlas Cluster to store users instead of having a separate users database managed outside of Atlas, as the case is today.
To avoid a breaking change, this could be implemented as an option to how users are managed today.
This would solve most user-related feature requests and issues, as it would give the app developer full control of the user DB to do whatever queries or customization they want to. Maybe call the option "advanced" or such—more manual labor, more control, for those who want that. I'd even be fine if all auth methods except JWT were disabled when the "Store users in Atlas collection" option is enabled if that helps the implementation.
I get that if someone makes incompatible changes, it could break the auth and access system, but that almost goes without saying, and I think that would be an acceptable compromise.
In my use case, we have an app (https://bikerider.app/) running Atlas with a separate custom GraphQL node server, and I was looking at Realm Cloud to simplify our backend (e.g., the goal would be to replace our node servers with Realm Cloud). That said, we already have a user collection, so with how Realm Cloud is working, I am going to see if I can use our existing users' collection as "custom user data" and use JWT for auth since we already have a custom auth system. But there may be issues with IDs etc. Since we already have relationships between different users and other entities (ex cycling events) based on our existing user IDs and Realm Cloud will create new user IDs. Not 100% sure about this yet, I will need to explore more and see if it can be mapped somehow, but I believe it would help a lot if I could say which collection to use for Realm users.
Related to (would be solved as part of this feature):
And so on.